Underbody paint advice needed

[Ozyduster]

So i am pretty much ready to spray the underside of car with colour matched Raptor liner however have a few questions:
-Obviously the rear of car is simple to figure out where to stop the underbody protection, with the front where did you guys underbody coat to? I am thinking stopping under the fire wall seam, spraying the rails and all inner fender (back of the shock towers) as well as back of the fenders. Maybe stop at the lowest point of rad support as well?
-The raptor liner is thick, for example where the leaf brackets and other items bolt on did you still coat or? Would it make bolting brackets back on difficult or will it simply crush the paint? Does it make installing rubber grommets a pain etc
-I will put greece in the bolt holes to avoid filling with paint
-Do i need to scuff up the primer or can i just spray Raptor straight over?
-The whole car was sand blasted any particular areas under the car that should be seam sealed? Wheel tubs already done!
-Should i also spray anything in the rails etc or dont bother? If so what products did you use?

Diff and all brackets will be dropped as well as the entire k frame and front end

 

[Syleng1]

1) read the directions on what the supplies you have require.
2) truck bed line on your floors? Sorry your car not mine but that is going to be a pain to clean dirt and hold moisture between the metal and the liner. Allowing rot to spread easy. I did that on a cab of a 72’ W200. Sand blasted spotless and allowed the Rhino lining process to do their thing. Professionals. With in 3 years the floors rotted out. Everything perfect to the t. I know off road guys swear by it and my truck was used every day.
3) I wish you luck with this process. I hope your car turns out better than my old power wagon did.

 

[Ozyduster]

1) read the directions on what the supplies you have require.
2) truck bed line on your floors? Sorry your car not mine but that is going to be a pain to clean dirt and hold moisture between the metal and the liner. Allowing rot to spread easy. I did that on a cab of a 72’ W200. Sand blasted spotless and allowed the Rhino lining process to do their thing. Professionals. With in 3 years the floors rotted out. Everything perfect to the t. I know off road guys swear by it and my truck was used every day.
3) I wish you luck with this process. I hope your car turns out better than my old power wagon did.

Car probably will not even see rain, my ute which had a ground up rebuild 8 years ago maybe seen rain twice however since 2019 averaged about 500km lol.
Lot of guys here in Aus use raptor liner as under body protectant as you can tint it plus also gives sound deadening and stone chip protection. Its also two part so better than a lot of others.
I would say you potentially had rust already etc as why is moisture getting in if its sealed?

 

[A56]

If you've already had a ground up rebuild on your UTE and you used raptor liner on it wouldn't most of the answers to your questions be answered? Or maybe I misunderstand your quandary.

 

[plymouth4onthefloor]

scotch it with silicon ex, wipe it with paint shop towels and silicon ex. close all the holes . use 2k epoxyprimer not rattle can! fill sheet metal gaps with a brush if necessary. allow to dry for a week. scotch the primer and clean with silicon ex. seal the gaps with sprayable and paintable highflexible underbodycoating. give in the wheel areas a structure coating. if you wish you can use it for the underflooring. i would stop at transtunnel / firewall seam. engine bay only 2k epoxy.

 

[Ozyduster]

Didnt use raptor on the underside it was chassis black and stone guard, used raptor in the tub only.

If you've already had a ground up rebuild on your UTE and you used raptor liner on it wouldn't most of the answers to your questions be answered? Or maybe I misunderstand your quandary.

 

[plymouth4onthefloor]

by the way, remove the axle, that thing will piss you off during painting

 

[mopowers]

I used raptor liner for the rear part of the interior in my '66 Dart. I wouldn't worry too much about the thickness at the spring mounts etc. If you're worried about it, you can always go a little lighter in those areas. Or, you could avoid them all together (assuming you plan on using a shutz gun), then thin some material out and hit them with an HVLP gun instead. Don't worry about the plug/grommet holes either. They'll slide right in afterwards.

I'd be careful, about using grease in the bolt holes too. If you do, be very careful to clean off any that gets smeared around the hole where you want to spray with the raptor liner. Maybe use a wad of tape instead, or an old bolt? You could always chase the threads afterwards too.

Read the TDS - it should call out what prep is suggested. I would definitely scuff the primer with a red scotchbrite prior to shooting the raptor liner. You want that mechanical adhesion. I had one small area that lifted a little that I had to touch up. I chalked it up to lackluster prep in that spot. It was easy enough to repair though. This stuff really is dummy proof. Good luck with your project! Here's a shot (albeit a tad blurry) of when I did mine last year.

 

[str12-340]

sorry, I'm just not getting this... why are you putting anything other than primer and paint on it ???

 

[Ozyduster]

Didnt use raptor on the underside it was chassis black and stone guard, used raptor in the tub only.

I used raptor liner for the rear part of the interior in my '66 Dart. I wouldn't worry too much about the thickness at the spring mounts etc. If you're worried about it, you can always go a little lighter in those areas. Or, you could avoid them all together (assuming you plan on using a shutz gun), then thin some material out and hit them with an HVLP gun instead. Don't worry about the plug/grommet holes either. They'll slide right in afterwards.

I'd be careful, about using grease in the bolt holes too. If you do, be very careful to clean off any that gets smeared around the hole where you want to spray with the raptor liner. Maybe use a wad of tape instead, or an old bolt? You could always chase the threads afterwards too.

Read the TDS - it should call out what prep is suggested. I would definitely scuff the primer with a red scotchbrite prior to shooting the raptor liner. You want that mechanical adhesion. I had one small area that lifted a little that I had to touch up. I chalked it up to lackluster prep in that spot. It was easy enough to repair though. This stuff really is dummy proof. Good luck with your project! Here's a shot (albeit a tad blurry) of when I did mine last year.

View attachment 1716235982

Thanks for the info, yep found it super easy to do in the tub of my ute but was 8 years ago lol. Any my panel beater mate helped. Looks good mate!!

 

[Ozyduster]

sorry, I'm just not getting this... why are you putting anything other than primer and paint on it ???

Because its not 1974 any more, and for multiple reasons.
It doesn't chip like standard paint, way more durable
-Has sound and heat resistance capabilities. I will also dinomatt floor pan topside and use a heat proof underlay with matting in it
-Some people argue its a lot better than traditional stone guards like Wurth etc
-Modern cars have stone guard in wheel wells and sound deadener to under side of car
-If you have welded in patches etc it neatens up any slight imperfections as it is textured
-Very easy to apply and limited prep although my car was bare metal, acid wash and primed

I am not building a factory car its going to be far from original so not worried about any of that

 

[WymanV]

Dynamat and spray-on bed liner? Sounds heavy. And not in a Marty McFly/Doc Brown sorta way.

When I did mine I painted all the structural parts (frame rails, etc.) and undercoated the sheet metal. Overspray was had but it's a black car so I didn't have a problem with that.

 

[Ozyduster]

Dynamat and spray-on bed liner? Sounds heavy. And not in a Marty McFly/Doc Brown sorta way.

When I did mine I painted all the structural parts (frame rails, etc.) and undercoated the sheet metal. Overspray was had but it's a black car so I didn't have a problem with that.

Not really you talking a few liters of paint be lucky if a few kg, the dyno matt would have a little weight but the difference it makes is amazing. I remember when i did my first angry car with it, my feet used to sweat from the pipes heating the floor up, it stopped that and just the road noise it cut out was massive. I will have 550-600hp so few kg isnt an issue

 

[Red383]

I used Color matched Raptor Liner on my Dart. I sprayed Epoxy on the bottom and then sprayed the Raptor the next day, which was within the recoat window of my epoxy primer. If yours is outside the recoat window, you may want to go over the primer with a scotch brite pad to give it a little tooth.

I masked off the areas where the leaf spring perches, and other items bolt to, but I did not mask off the trans mount area, which made it more difficult to install due to the thickness, but a little Tap-Tap with the dead blow and it went in place. I stopped my Raptor at the pinch weld at the bottom of the firewall and then masked off the frame rail. You can see the tape line in this picture.

 

[Ozyduster]

I used Color matched Raptor Liner on my Dart. I sprayed Epoxy on the bottom and then sprayed the Raptor the next day, which was within the recoat window of my epoxy primer. If yours is outside the recoat window, you may want to go over the primer with a scotch brite pad to give it a little tooth.

I masked off the areas where the leaf spring perches, and other items bolt to, but I did not mask off the trans mount area, which made it more difficult to install due to the thickness, but a little Tap-Tap with the dead blow and it went in place. I stopped my Raptor at the pinch weld at the bottom of the firewall and then masked off the frame rail. You can see the tape line in this picture.

View attachment 1716236926

Is the black raptor liner as well looks like has texture in parts of it? Appreciate this post pretty much gives me exact answer. I was thinking of doing the front wheel arches as well

 

[Red383]

The black is rubberized under coat. The heavy textured black areas are the original under coating. It was stuck really good, so I just cleaned it and sprayed the new over the old. The new turned out a lot smoother that the original, but I am ok with that. No body is going to be inspecting my wheel wells that close. ;-)

 

[Ozyduster]

The black is rubberized under coat. The heavy textured black areas are the original under coating. It was stuck really good, so I just cleaned it and sprayed the new over the old. The new turned out a lot smoother that the original, but I am ok with that. No body is going to be inspecting my wheel wells that close. ;-)

I feel your pain mate we removed all the old sound deadening and was like **** on a blanket took crazy amount of time. Why didnt you use the raptor liner in the wheel wells?

 

[harrisonm]

I have used a similar product. You should be fine with the possible rust if it is not driven in rain much. I would scuff with more than a scotch brite pad. I would scuff with 220 or 320 grit dry paper. that will give good mechanical adhesion, and the minor sanding scratches will be more than covered with the thick product.

 

[Red383]

I feel your pain mate we removed all the old sound deadening and was like **** on a blanket took crazy amount of time. Why didn't you use the raptor liner in the wheel wells?

I guess my though was that the Rubberized undercoat would dampen the sound of rocks and stuff in the wheel wells better than the Raptor.